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Discussion Starter · #1 ·
I ran this O2 sensor eliminator for 20k miles with no CEL or issues. I have now removed for a A/F ratio gauge and thought it would be worth it to share. You are actually modifying your existing o2 sensor by putting capacitor and resistor inline, similar to the universal ones sold on ebay for 15+ dollars, except this only cost about 3 dollars or less.

tools needed: wire cutter and strippers, soldering iron or small butane torch.

Parts needed: 1MFD capacitor (Radioshack Part#2721434)
1MEG 1/4w Resistor (Radioshack Part#2711356)
wire 18 gauge will do fine
shrink tubing
You don't have to use wire i just chose to build the harness then attach it inline

Step1: Cut two pieces of wire roughly 6 inches, strip wire in the middle of the wire to bridge the two wires using the capacitor, wrap wires of capacitor around bare wire and solder.


Step2: On either wire midways between capacitor and end of wire cut it, strip both ends and solder resistor inline.


Step3: Put shrink tubing on both legs of capacitor to isolate them from each other, then put shrink tubing over the entire resistor, then i chose to take one big piece and put it over the entire assembly for added protection. Be sure you remember where the resistor is located and which wire.



Step4: Time to connect to the O2 sensor. Cut the gray and black wire on your O2 sensor midways between the connector and the sensor. Connect the wire with the resistor inline to the black wires, resistor goes on the sensor side. Next connect the other inline with the gray wire. I used but connector with built in shrink tubing for this part or you can solder. Then tape up everything making sure all bare wire is isolated from each other.




It may not look as nice as the 40 dollar ones but you won't care when it works and you got money left on your wallet. I you put shrink tubing over the entire thing it would probably look a lot better than my tape job.
 

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Discussion Starter · #3 ·

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Discussion Starter · #5 ·
If your talking about my mod to the O2 sensor yes , never had a single check engine light in 15k+. As for Tom's I'm not sure never tried it, but I would assume so.
 

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I've been running an anti-fouler for awhile now; the 18mm thread, longer version is what I have. I think I had to bore it out with a 1/2" drill bit, I didn't drill all the way through.
 

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So what is the reason for the O2 sensor eliminator? Also I know it says anti-fouler and its obvious intention, but why are people running them? Are they on tuned engines or boosted engines?
 

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BACON?
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If your talking about my mod to the O2 sensor yes , never had a single check engine light in 15k+. As for Tom's I'm not sure never tried it, but I would assume so.
so, its better then a MIL cheater then. I get a CEL for my cat every couple months.
 

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So what is the reason for the O2 sensor eliminator? Also I know it says anti-fouler and its obvious intention, but why are people running them? Are they on tuned engines or boosted engines?[/

If you don't have a cat or even have hfc without the rear o2 turned off in the tune the engine light will stay on the antifouler moves the sensor out of the pipe and gives a false reading tricking the car turning off the light. This crazy wiring seems to be easier to hide for inspections
 

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Discussion Starter · #10 ·
So what is the reason for the O2 sensor eliminator? Also I know it says anti-fouler and its obvious intention, but why are people running them? Are they on tuned engines or boosted engines?
You run them when you have removed the cat to fool the ECM, it modifies the signal to make it look like there is still a cat and it's doing its job, the antifouler sets the o2 sensor out of the main exhaust stream so it won't read the exhaust(or something like that)
 

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Thats interesting thanks for the explanation guys.
 

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I think the anti fouler only works if you have a tune with the o2 delete, right? Isn't it not going to heat up to operating temperature?
 

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Now why would you need to trick a sensor that's turned off anti foulers allow the sensor to heat up and keeps it out of the exhaust stream
 

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Discussion Starter · #14 ·
yeah if you have a tune you can just completely remove the post cat o2 sensor
 

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Right, but my experience with decreasing the depth of the o2 sensor is that is still doesn't get up to operating temp, throwing a code. But I only tried this on an older car I owned (Mazda Protege) so maybe the Focus ECU is less picky about o2 sensor heater circuit. Obviously a tune removes the nead to put a anti fouler in so its kind of redundant to have both, which is why i was confused if you needed a tune anyway. The only O2 cheater I've seen that worked are the ones that are included with high-flow cats or ORP's, which are fancy simulators.
 

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I think the anti fouler only works if you have a tune with the o2 delete, right? Isn't it not going to heat up to operating temperature?
Not right.......i put a HFC from jays racing on my car 9-10 months ago and about 4 months ago i got a CEL and a serious rattle from my exhaust. I pulled the HFC and all of the catalis (spelling?) inside the cat had blown out. That was my rattling. I put the non-fouler on the rear O2 and no CEL.

All it does is takes the O2 sensor out of the direct flow of the exhaust and the little hole in the non-fouler lets in just enough exhaust to read good.

Oh BTW....i have no tune!
 

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yeah if you have a tune you can just completely remove the post cat o2 sensor
I want to do this for my motorcycle, but the thing is my sensors have tow wires not four, one ground wire one signal wire. How can I eliminate the O2 sensors.
 
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